Secretion, the formation of lysosomes and receptor-mediated endocytosis are all mediated by vesicular packaging and transport. Intraorganelle communication also involves the transport of vesicles. Some of these transport processes utilize nucleotide-sensitive microtubule-binding proteins to power the vesicles along microtubules. The vesicle and vacuole in the phagosomal system in Paramecium have been shown to be transported along at least three different well defined microtubule systems, the oral microtubular ribbons that span the oral region and the cytoproct, the postoral fiber consisting many bundles of microtubules and the microtubules arising from the cytoproct and the adjacent basal bodies. A logical extension of these previous studies is to characterize the motor(s) responsible for the three movements. As we have purified one group of motors, the cytoplasmic dyneins, we proposed to investigate the possibility that kinesin, a second group of motors, may be present in Paramecium. We will purified kinesin and to monoclonal antibodies to kinesin to determine the location of this motor in the cell and to probe its in vitro and in vivo functions. New information on how normal cells direct and regulate vesicular transport is the goal of this proposal.